Unexpected Rearrangement in the Reaction of 7‐Mercapto‐4‐methylcoumarin with 1‐Mono‐ and 1,1‐Dimethyl Propargyl Alcohols

Abstract

The reaction of 7‐mercapto‐4‐methylcoumarin (4) with 1‐mono‐ and 1,1‐dimethyl propargyl alcohols in H₃PO₄ afforded the corresponding β‐(7‐coumarinthio)ketones with a rearrangement of the carbon chain of propargyl. A possible mechanism of this rearrangement was proposed.

Keywords:

• β‐(7‐coumarinthio)ketone
• 7‐mercapto‐4‐methylcoumarin
• propargyl alcohol
• rearrangement

Acknowledgment

This research was supported by grants from the National Natural Science Foundation of China (Nos. 20272010 and 30200348) awarded to P. Xia and Y. Chen, respectively, and the research grant (No. 2002046069) from the National Education Administration of China awarded to P. Xia. In addition, we express our sincere thanks to Tamejiro Hiyama for his kind discussions.